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Finding the Third Proportional to 309.94 and 685.69

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Solution

The third proportional to 309.94 and 685.69 is: 1,516.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.94 : 685.69 = 685.69 : x
  2. Step 2: Convert to fraction form
    309.94/685.69 = 685.69/x
  3. Step 3: Cross multiply
    309.94x = 685.69 × 685.69
  4. Step 4: Simplify right side
    309.94x = 470,167.35
  5. Step 5: Solve for x
    x = 470,167.35/309.94
  6. Step 6: Final answer
    x = 1,516.97

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Why These Related Problems?

These problems maintain the same ratio (2.21) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.